The present invention relates to arrangements for securing fire hydrant operating valves. More particularly, the present invention relates to magnetically operated devices for securing fire hydrant operating valves.
Municipal and county water departments are frequently confronted with unauthorized use of fire hydrants by members of the public, who, on occasion, open the valves of the hydrants to obtain water to cool-off on hot days or for the purpose of filling tank trucks with fresh water which is then sold for various purposes, such as filling swimming pools. In cities, open fire hydrants can result in a drop in water pressure to customers and can occasionally endanger a community by reducing the availability of water necessary to fight fires.
In attempts to secure fire hydrants from unauthorized use, fire companies have employed locking devices such as the magnetic valve locks of U.S. Pat. Nos. 4,620,428 and 5,596,893. The particular valve lock disclosed in the ""428 patent utilizes a magnetic detent, normally disposed in a center post fixed to a hydrant operating nut, to couple the operating nut of the fire hydrant to an outer body in the form of a capped sleeve, which is normally freely rotatable with respect to the hydrant operating nut. The magnetic detent is attracted by a second magnet permanently mounted in a wrench which cooperates with the outer body to rotate the outer body. Upon coupling the outer body to the center post, rotation of the outer body by the wrench rotates the hydrant operating nut to release water from the hydrant. In the ""428 patent the center post is attached to the valve operating nut of the hydrant by a pin that passes laterally through both the center post and the hydrant operating nut. Since the pin has a relatively small diameter, persistent vandals have an opportunity to defeat these devices.
The ""893 patent discloses a center post configured inner sleeve with a polygonal opening for receiving the operating nut of the fire hydrant. Since the particular valve lock of ""893 patent is only suitable for use with a valve operating nut of one size and configuration, it is necessary to have a different center post for different sized and configured hydrant operating nuts. In that the center post is a brass casting, considerable expense is involved in maintaining an inventory of center posts that are compatible with most, if not all fire, hydrant operating nuts. This problem becomes acute when replacing old fire hydrants with new fire hydrants that may have different hydrant operating nuts. A frequent response is to dispose of these magnetic valve locks and buy new ones at considerable expense.
In view of the aforementioned considerations, a valve operator securing arrangement is provided for fire hydrants having valve stems connected to hydrant operating valves wherein the valve stems have hydrant operating nuts with particular polygonal exterior shapes. Rotation of the valve stems by gripping and rotating the hydrant operating nuts opens and closes the valves. The arrangement includes a device comprising a center post having a first end with a first recess of a selected shape therein, which first recess opens outwardly therefrom. The center post also has a second end defining a first coupling element. At least one insert is disposed non-rotatably within the recess of the center post. The insert has an axial opening therein of a polygonal shape complementing the polygonal exterior shape of the hydrant operating nut for non-rotatably receiving the hydrant operating nut therein, wherein rotation of the center post positively rotates the hydrant operating nut. An outer body is rotationally mounted over and around the center post for rotation with respect to the center post. The outer body includes a second coupling element. A movable magnetizable element is provided which is urged to a first position, decoupling the first and second coupling elements, and is movable to a second position coupling the first and second elements in a non-rotational relationship, wherein rotation of the outer body rotates the center post to rotate the valve stem and operate the valve. Upon employing a wrench with a permanent magnet and mechanically interlocking the wrench with the outer body, the outer body is enabled for rotating the hydrant operating nut when the magnetizable element is moved from the first to the second position.
In a further aspect of the invention, the particular polygonal exterior shape of the hydrant operating nut is a pentagon, a square or a hexagon.
In a further aspect of the invention, the first recess in the center post has a polygonal shape and the insert has a polygonal exterior shape which compliments the polygonal shape of the recess to lock the insert and center post in a non-rotatable relationship.
In a still further aspect of the invention, the insert is slidable into the first recess in an axial direction.
In a still further aspect of the invention, the arrangement comprises a system having plurality of inserts each having the same exterior shape as the shape of the first recess and each having an axial opening of a polygonal shape complementing one of the particular polygonal exterior shapes of the hydrant operating nuts.
In still a further aspect of the invention, the selected shape of the first recess in the center post and the exterior shape of each insert is pentagonal.